Improving patient outcomes following mandibular reconstruction after oral cancer: novel finite element methods for better surgical design

Description

Within Cheshire & Merseyside over 1,000 individuals a year are diagnosed with head and neck cancer, with some central city wards having 4 times the UK average. Oral cancer is frequently diagnosed at a locally advanced stage. Surgical management of these tumours commonly involves reconstruction to restore both facial form and vital functions of daily living following surgical resection of the mandible. The gold-standard for reconstruction of such defects is the use of free flaps of vascularized autologous bone sourced from one of a variety of suitable donor sites. Fibula free flap and radial forearm free flap are among the most commonly used to reconstruct the mandible, although iliac crest and scapular flaps can also be used for reconstruction of tooth-bearing segments and osteo-cutaneous reconstruction for mandibular and maxillary segments. In each case, the ambition is to restore both bony continuity of the lost tooth-bearing segments and facial form. However, the choice of the reconstructive element can impact the geometrical shape of the mandible after surgery, which can have an impact on its biomechanical behaviour (Cheng et al. 2021).

Extensive surgical reconstruction frequently alters both the mandibular form and its inherent strength. Changes in shape and muscular function/ability, can result in weakening of the construct, and its capability to withstand forces such as those generated during chewing (occlusal forces). This can cause the reconstructed element to be more fragile and result in fracture due to the accumulation of bone micro-damage from altered stress over a period of time. The restorative dental rehabilitation of these patients with implants supported prostheses is key to improving function, aesthetics and quality of life; however, this can only be achieved with an intact reconstruction of the combined maxilla-mandibular functional unit.

Improvements in technology, computational modelling and 3D printing offers a novel approach to surgical planning and restorative rehabilitation. Detailed, validated biomechanical models (e.g., finite element models) with accurate geometry and material properties are now possible, improving on past modelling approaches. These can identify regions at risk of post-operative failure and facilitate improvement in the preoperative patient-specific planning that has become the norm for complex composite defects.

Study Aims and Objectives

This study aims to characterise biomechanical behaviour of complex mandibular reconstructions and to provide an accurate determination of the functional loadings of the mandible and its reconstructive element using finite element analysis (FEA). The ultimate goal of this work is to provide clinically relevant information to identify the best free flaps for planning of surgeries and improve postoperative performance.

We will address the main question: do different reconstructive elements and different surgical techniques influence the function of the TMJ, the mechanical environment of the combined mandible and reconstructive element, and muscle loading during chewing?

Student specifics and training

We are looking for a motivated candidate with a high 2.1 or 1st class degree in Anatomy, Biomechanics, Mechanical Engineering, or with equivalent relevant expertise.

Training will be provided throughout the study in several ways. Project-specific hands-on training will be provided by the supervisory team and colleagues as needed and following regular Development Needs Analysis. This will include lab inductions, health and safety training, seminars, outreach opportunities and journal clubs. As a member of the Liverpool Doctoral College, a wide range of additional training resources will be available. The student will have regular (at least monthly) formal meetings with the supervisory team and yearly meetings with two assigned Academic Advisors.

The University is fully committed to promoting equality and diversity in all activities. In recruitment we emphasise the supportive nature of the working environment and the flexible family support that the University provides. The Institute holds a silver Athena SWAN award in recognition of on-going commitment to ensuring that the Athena SWAN principles are embedded in its activities and strategic initiatives.

To apply: please send your CV and a covering letter to Dr Alana Sharp alana.sharp@liverpool.ac.uk